Farmers might have to pay for their emissions like everyone else under a revision of the Government's main climate change policy.
The Emissions Trading Scheme (ETS), which puts a price on greenhouse gas emissions, is being reviewed this year.
A briefing paper produced for the Government by the Ministry for the Environment said it expected the review to consider agriculture's entry into the scheme.
A ministry spokeswoman said this did not amount to a recommendation to the Government and was simply a comment on the scope of the review. The terms of reference had not yet been determined by the Cabinet, she said.